Reforming with alumina-chromiaboria catalyst



May 9, 1961 R. M. DoBREs ET AL 2,983,672

REFORMING WITH ALUMINA-CHRoMm-BORIA, CATALYST Filed April l. 1958 UnitedStates Patent O REFORMING WITH ALUMINA-CHRGNHA- BURIA CATALYST Robert M.Dobres, Silver Spring, Md., and Barton W. Rope, Mullica Hill, NJ.,assignors to Socony Mobil Oil Company, Inc., a corporation of New YorkFiled Apr. 1, 1958, Ser. No. 725,555

6 Claims. (Cl. 208-136) This invention relates to a catalytic compositeespecially useful in reforming petroleum hydrocarbons. Moreparticularly, the present invention is ydirected to an improvedcatalytic reforming process for obtaining gasoline of high octane numbercarried out in the presence of a catalyst consisting essentially of aco-gelled chromiaalumina composite of particularly defined compositioncombined in a particular manner with a specified minor proportion ofboria and to the resultant catalytic composite.

Reforming operations wherein hydrocarbon fractions such as naphthas,gasolines and kerosene are treated to improve the anti-knockcharacteristics thereof, are well known in the petroleum industry.Reforming is generally carried out by contacting the hydrocarbon chargeat an elevated temperature in the presence of hydrogen with "volume ofhydrocarbon per hour per Volume of catalyst,

is between about 0.1 and about 10 and preferably between about 0.5 andabout 4. In general, the molar ratio of hydrogen to hydrocarbon chargestock employed is between about l and about 20 and about 4 and about 12.

Hydrocarbon charge stocks generally subjected `to reforming comprisemixtures of hydrocarbons and particularly petroleum distillates boilingwithin theA approximate range of 60 F. to 450 F. which range includesgasolines, naphthas, and kerosene. The gasoline fraction may be a fullboiling range gasoline or a selected fraction such as naphtha having aninitial boiling point of between `about 150 Fr and about 250 F. and anend boiling point of between about 350 F. and about 425 F. Straight rungasolinas generally contain naphthe-nic hydrocarbons, particularlycyclohexane and related compounds and parailinic "hydrocarbons'which areusually of straight chain or slightly branch chain structure, as well aslvarying proportions of aromatic hydrocarbons. During reforming, amultitude of reactions take placeQincluding isomerization,`dehydrogenation, cyclization, etc., to yield a product of increasedaromatic content. Thus, in reforming, it is desired to dehydrogenate thenaphthenic hydrocarbons to produce aromatics, to cyclize the straightchain paraffinic hydrocarbons to form aromatics, and to elect acontrolled type of cracking which is` selective both in quality andquantity.`

` Controlled or selective cracking is highly desirable during reformingsince such willresult in a product of antiknock characteristicsl` As a`general `rl`1le,. tl`1e`Y lower preferably between i 'ice molecularweight hydrocarbons exhibit a higher octane number, and a gasolineproduct of lower average molecular weight will usually have a higheroctane number. In addition, the isomerization and molecularrearrangement which occur during reforming also result in productshaving higher anti-knock characteristics. The splitting or cracking ofcarbon to carbon linkages must, however, be selective and should be suchyas Vnot 'to result in substantial decomposition of normally liquidhydrocarbon into normally gaseous hydrocarbons. The selective crackingdesired ordinarily involves removal of one or two lower alkyl groups,such as methyl or ethyl, from a given molecule in the form of methane orethane. Thus, during reforming, it is contemplated that heptane may beconverted to hexane, nonane to octane `or heptane, etc. Uncontrolledcracking, on the other hand, would result in decomposition of normallyliquid hydrocarbons into normally gaseous hydrocarbons. For example,non-selective cracking of normal octane would ultimately lead to eightmolecules vof methane.

Uncontrolled reforming, moreover, generally results in rapid formationand deposition on the catalyst of large quantities of a carbonaceousmaterial generally referred to as coke The deposition of coke on thecatalyst surface diminishes or destroys its catalyzing effect `andresults in shorter processing periods with the accompanying necessity offrequent regeneration by burning the coke therefrom. In those instanceswhere the activity of the catalyst is destroyed, it is necessary to shutdown the unit, remove the deactivated catalyst, and replace it with newcatalyst. Such practice obviously is time-consuming and inecient,imparting a greater over-al1 expense to the reforming operation.

The choice of catalyst for promoting reforming of hydrocarbons togasolines of enhanced octane rating is dependent on several factors.Such catalyst should desirably be capable of effecting reforming in acontrolled manner as discussed above to yield la product of improvedanti-knock characteristics. The catalyst selected should further beresistant to poisoning and particularly to sulfur poisoningso .thatsulfur-containing stocks may undergo reforming without the necessity ofsubjecting the same to a preliminary treatment for desulfurzation. Thecatalyst also should desirably be characterized by high stability yandbe capable of easy regeneration, and the method for preparing suchcatalyst should be commercially attractive, requiring a minimum ofequipment and processing stages.

ln accordance with the present invention, a catalyst of the`above-defined` characteristics has been discovered. Broadlyhythepresent invention comprises reforming hydrocarbon mixtures and,particularly a naphtha fraction of petroleum in the presence of acatalystconsisting essentially of 'co-gelled chromia and aluminacombined .with a minor proportion of boria. The invention further tionconsisting essentially of ,co-gelled chromia-alumina y composited withboria have unexpectedly, been found to have improved reforming activityin comparison with chromia-alumina composites.

The method of reforming petroleum hydrocarbons in the presence of aco-gelled chromia-alumina composite combined with boria as describedherein has been found to have certain advantages over the processescommercially available. The advantages obtained upon reforming with thepresent catalyst, while not fully understood, are believed to resultfrom the method of preparation of the catalyst employed. The presentcatalyst initially involves the formation of a hydrogel of chromia andalumina preferably containing a chromia-alumina content of at leastpercent by Weight and thereafter combining the washed hydrogel withboria.

Boria may be combined with the co-gelled chromiaalumina by impregnatingeither the washed hydrogel or the dried and tempered chromia-aluminacomposite with a solution of a boron compound, followed by drying andcalcining of the impregnated product. A preferred embodiment of theinvention is the catalytic composite Vresulting from intimate admixing,for example, by ballmilling chromia-alumina hydrogel and a compound ofboron, thermally decomposable to boron oxide, together, until ahomogeneous composite is obtained and subsequentlydrying and calciningat an elevated temperature 'sufficient to effect decomposition of thecompound of boron employed to boron oxide but not exceeding about In oneembodiment chromia-alumina hydrogel containing, on a dry basis, about toabout l45 percent by Weight of chromia and about 55 to about 85 percentby weight of alumina and having a solids content of at least about 10percent by weight and generally in the approximate range of 10 to 30percent by weight, i.e. containing about 70 to about 90y percent byweight of water, is ball milled with a finely divided solid boroncompound, thermally decomposable to boron oxide, and subsequently driedand calcined at an elevated temperature. The amount of boron compoundused may be varied depending on the catalyst composition desired `and onthe particular compound of boron employed. Boric acid is particularlypreferred as a source of the boria component. After intimately admixingby ball milling or other suitable means, the resulting composite isdried and calcined at a temperature sufiicient to elect decomposition ofthe boron compound employed but not in excessof about 1000" F. Theycomposite catalyst consisting essentially of a co-gel of alumina andchromia combined with boria is thereafter ready for use.

Composites consisting of a major proportion of alumina, a minorproportion of chromia and a minor pro.-

portion of boria are suitably prepared in accordance with the abovemethod. Catalysts having a composition of 10 to 30 percent by weight ofchromia, 50 vto 89 per- Vcent by Weight of alumina and l to 20 percentby Weight of boria areV unusually effective for promoting reformingcontaining reforming catalyst. The co-gel of chromiaalumina is a truegel prepared by forming a hydrosol of chromiaand alumina and permittingsaid hydrosol to set to an all-embracing hydrogel. 'Ihe hydrogel issuitably in particle form prior to admixture with the boron compound.The particles may be of irregular size such as those produced bybreaking up a previously set hydrogel or the particles may be of auniform size and shape. Preferably, the alumina-chromia hydrogelparticles are in the form of spheroids prepared by introducing thehydrosol in the form of globules into a waterirnmiscible medium whereinthe hydrosol globules set to spheroidal hydrogel particles. It isparticularly preferred to prepare a co-gelled catalytic composite ofchromia and alumina from a hydrosol having an inorganic oxide content ofat least about 10 percent by weight in accordance with the processdescribed in U.S. Patent No. 2,773,839 to Stover and Wilson. Suchprocess has been set forth in detail in the aforementioned patent. Forconvenience herein, the following is offered as a brief description ofsaid process.

A true, all-embracing chromia-alumina hydrogel having a metal oxideproduct concentration of at least about 10 percent by weight and arelatively short gelation time, i.e.', less than 2 hours and preferablyless than seconds, is prepared by intimately admixing an organicchromium salt, such as chromic acetate, and an alkali metal aluminate,such as sodium aluminate to produce a chromia-alumina hydrosol. Thehydrosolv so formed is permitted to set to a hydrogel. 4The resultinghydrogel is thereafter subjected to aging and then waterwashed. Therelative proportions of chromia and alumina may be Varied over a widerange. In accordance with the instant invention, however, theconcentrations of reactants employed should be such as to afford achromia-alumina hydrogel of composition within the range set forthhereinabove.

It is preferred, in preparing the above-described hydrogels, to useaqueous solutions of sodium aluminate and chromic acetate. Neither ofthese substances is a true chemical compound. The ratio of sodium toaluminum can be varied widely as can the ratio of acetate to chromiumion. Variation in the sodium to aluminum ratio of the aluminate solutionrequires compensating adjustment of the acetate to chromium ratio of thechromic acetate solution in order to achieve satisfactory gelation.Hydrosols capable of setting to hydrogels in less than about 20 secondsare particularly desirable for the production of beadlike spheroidalparticles by methods well known in the art, for example, those describedin patents to Marisic, such as U.S. Patent No. 2,384,946.

Quick-setting hydrosols of low viscosity which can be readily handled atbead-forming nozzles are those'prepared from sodium valuminate solutionswhich havek a sodium to aluminum mole ratio referred to as R of between1 and 1.5. The acetate to chromium mole ratio in the chromic acetatesolution employed should be not less than 2.8R-1-8 and not more than4R-2.3

thermally decomposable solid boron compound, i.e. boric acid, representsa` preferred embodiment of the invention and has been found to afford animproved yield OfrefOrrnate of the same octane number as compared to `anvoperation carried out under identical reforming conditions employing achromia-alumina gel catalyst of 1 and preferably in the range of 4R-2.8to LfR-2.4.

The control of the mole ratios discussed above is readily achieved inthe manufacture of reactant'solutions. Chromium acetate is readilyformed without introduction of undesirable extraneous materials byreducing sodium dichromate with glycolic acid in the presence of aceticacid as described more fully in U.S. 2,615,031.

- Sodium aluminate is conveniently prepared from caustic soda of 50 B.and aluminum trihydrate. At a sodium to aluminum mole ratio in the rangeof 1.25/1 to 1.5/ 1, the sodium aluminate is advantageously manufacturedin an open agitated kettle at 22o-230 F. with` a reaction time of 1 to 3hours. Solutions having a lower mole ratio downto about 1.0/1 are madein an autoclave Vat 2410-300or F. vand 10 to 30 pounds per square inchgauge at the same reaction time. Sodium aluminate solutions having a lowsodium to aluminum ratio less than 1.3 are relatively unstable and maybe stabilized `hyd-rides,` such as di-borrane.

by the addition of such organic materials as glycerne, starch, sugar,and the like.

Thus, chromia-alumina hydrogels having a short time of set and a highsolids content generally between about and about 30 percent by Weightmay readily be prepared by controlling the sodium to aluminum mole ratioof the sodium aluminate solution employed and the acetate to chromiummole ratio of the chromic acetate solution. The specific ratios employedwill depend upon the particular composition of the chromia-aluminahydrogel desired.

Temperature, acidity, and product concentration are interrelatedvariables effecting gelation and within the limits in which formation ofhydrogels occurs they control gelation time. In general, the otherfactors can be controlled to achieve gelation at any practical solutiontemperature. Thus, temperatures from 30 F. to 150 F. are suit-able. Bestgelation times are experienced at temperatures between about 120 F. andabout 140 F. The pH of the chromia-alumina hydrogels is generallybetween 10 and 13. For bead formation, a pH of about l2 yields excellentresults.

For the production of chromia-alumina hydrogel beads, preparation iscarried out substantially the same as that described in the above notedMarisic patent for producing silica-alumina beads. `Thus, a chromiumacetate solution and a sodium aluminate solution are contacted in amix-ing nozzle and discharged onto the apex of a dividing cone fromwhich la number of small streams flow into a column of water-immiscibleliquid. The temperature of said water-immiscible liquid is desirablymaintained constant by circulation through a heat exchanger outside thebead-forming tower.

The freshly formed chromia-alurnina hydrogel above described is subjectto a loss of aluminum as sodium aluminate if immediately washed withwater. This tends to weaken the hydrogel to such an extent that itdisintegrates in the washwater. That adverse effect can be avoided byimmediately treating the freshly formed hydrogel in a slightly alkaline`aqueous medium.` This is generally accomplished by bringing the freshlyformed chromia-alumina hydrogel into contact, withl an aqueous solutionof an` ammonium salt of a mineral acid or a mineral acid or a mixture ofsuch salt and acid. In a typical operation, the freshly formed hydrogelbeadsare `sluiced out of the forming tower with oil. The hydrogel beadsare then separated from theoil and treated with a Z0 percent by weightsolution of ammonium sulfate. The solution is advantageously kept at @apH of 8.0 to 9.5 by the addition of sulphuric acid. lt is advisable tomaintain a solution of `this type in contact with the freshly formedhydrogelfor some time after formation. For example, the solution .-isreoirculated through the freshly formed hydrogel or otherwise maintainedin contact therewith for a period of,` from about, 2 to about 24 hoursafter forming in order to iixthe alumina. Such treatment of the freshlyformed hydrogel is designated herein as aging After the `agingtreatment, the chromialalumina hydrogel is water-washed free of anionsintroduced during aging. The washedhydrogel is thereafter ready forcompositing with boria. The combination of boria with thechromia-alumina hydrogel` involves intimate adm-ixture with saidhydrogel` of a solid boron compound, such as boric acid,decomposable byheating at a temperature of less than 1000 F. to boron oxide (B203),While boric acid, due to its availability and ease of decomposition, ispreferred, other suitable boroncoinpounds, decomposablefto boron oxideunder the conditions employed includeboric. acid esters of alcohols,such as triv ethyl -borate and-tri-lmethyl borate; boric acid esters ofpoly-hydric alcohols, such `as glycerol borate and `boron The boroncompound `is preferably in the form of a finely pulverized or powderedabout 70 to 90 percent by weight of water, is intimately mixed with thesolid boron compound in the `above indicated nely divided state.Vigorous and thorough ad- `mixture of the components is necessary toachieve. a

l period will, of course, depend on the relative amounts of each of thecomponents as well as on the total mass of material being treated.Generally, however, the mixing period will be within the range 'of 4 to20 hours.

At the `completion of the mixing operation, the resulting composite,either with or without intermediate formation of the same intoparticles, is slowly heated to an elevated temperature generally in therange of 800 to 1000 F., which temperature is sufficient to eifectdecomposition of the boron compound present to boria. The rate ofheating should be comparatively slow, generally not in excess of 10 F.per minute. It is essential to the success of the present invention thatthe temperature to which the composite of chrorna, alumina and boria isheated should not exceed about 1000 F. if such temperature issubstantially exceeded, fusion of the boria component takes place withaccompanying marked loss of `catalytic activity. During the period ofheating the wet catalyst, the atmosphere surrounding such catalystshould be desirably free of oxygen. This may be accomplished bymaintaining an inert atmosphere in contact with the catalyst during thecourse of heating. In a preferred embodiment of the process, anon-oxidizing atmosphere may be provided by permitting the steamproduced from the moisture contained in the wet catalyst to blanket the.same during heat treatment. The resulting catalyst is a compositeconsisting essentially of chromia-alumina gel intimately combined with acatalytically effect amount of boria.

The formation, compositing and subsequent heat treat- .ment ofchrornia-alumina-bonia composite in accordance with this -invention maybe carried out either as a batch or continuous operation. Thus, thechro-mia-alumina hydrogel particles after formation, aging and washingmay be ball milled or otherwise intimately mixed either on a batch basisor as part of a .continuous operation. Heat treatment of the compositedmaterial may also be effected in a batch .or continuous mannerGenerally, for commercial production, it is preferred to carry out themanufacture of the present chromia-alumina-boria catalyst' on acontinuous basis. A suitable continuous method of operation is shown inthe form of a schematic ow diagram in Figure l of the attached drawing.

Referring more particularly to Figure 1, a mixing nozzle 10 into whichare conducted aqueous streams of sodium aluminate and chrornic acetate,is mounted over a conical divider 11` which is located-near the surfaceof the water-immiscible liquid 'in forming tower 12. The colloidalsolutions from which the hydrogel particles are formed are mixed andadmitted through nozzle 10- to the top of the divider 11 which generallyis fluted and serves to divide the stream of hydrosol into a pluralityof smaller streams which enter the column of water immiscible suspendingliquid in tower 12 as: small droplets.

`The length of the column of suspending liquid and the gelation time ofthe sols are so regulated that the droplets will gel before passing outof the forming tower.

`Suspending liquid is continuously supplied through inlet Ydrainingsection and a iiushing section. The hydrogel material. Thechromia-alumina hydrogel, containing particles initially are conductedthrough the draining section wherein loosely held oil drains from theparticles into collecting pan 17. The oil so collected, thereafterpasses through conduit 18 and is recycled to forming tower 12 by way ofpump l19 and conduit 20. The hydrogel particles on the conveyor whichhave been drained-of loosely held oil pass into the flushing section andthere are flushed or sprayed with a suitable washing fluid through aspray 21. The resulting mixture of oil and washing iluid is collected inpan 22 and thereafter flows through conduit 23 to settling tank 24. Theoil contained in such mixture is removed from the lower portion of tank24 and passes through conduit Z5 to pump 19 and is then recycled throughconduit 20 to forming ltower 12. The washing fluid separating in theupper portion of tank 24 is withdrawn through conduit 26 and recycled tospray 21 for further `use in deoiling. Washing fluid make-up, as needed,is introduced through inlet 27. The chromia-alumina hydrogel particles,after being deoiled, are discharged from the conveyor belt into a flume28 and are conducted to againg tank 29 in with the hydrogel particlesare subjected to aging treatment in an aqueous media, such as an aqueousammonium sulfate solution.

After the aging treatment, the chromia-alumina hydrogel particles areremoved from tank 29 through conduit 30 and conducted to washing tank 31in which the hydrogel particles are water-washed free of anionsintroduced during aging. The washed hydrogel is then removed fromwashing tank 31 through conduit 32 and introduced to ball mill 33. Boricacid, in finely divided particle-form, is also introduced through inlet34 to ball mill 33. The washed chromia-alumina hydrogel and boric acidare intimately admixed in the ball mill. The ball-milled product is thenconducted to an extruder 35 wherein it is extruded to particles ofdesired size. The particles, so formed, are conducted to a kiln 36 inwhich the composite particles are dried and calcined at a temperaturenot in excess of about 1000 F. Water vapor removed from the particlespasses out of the kiln through outlet 37. The product ofchromia-alumina-boria catalyst passes from the kiln through outlet 38.

An alternate method of preparation for the cogelled chromia-aluminacomposite combined with boria as described herein involves contactingthe aged, water-washed chromia-alumina hydrogel prepared as hereinabovedescribed with an aqueous solution of a water-soluble boron compound. Inthis method of operation, the period of impregnation will generally bewithin the range of 2 to 48 hours. The impregnated composite isthereafter dried, preferably in superheated steam at a temperature of220-250 F. and subsequently tempered at an elevated temperature notexceeding about 1000 F. Also, in some instances, it may be desirable toprepare the catalyst by purging the dried, tempered chromia-alumina gelparticles under atmospheric pressure with steam at a temperature above24.12 F., thereby replacingthe air which normally occupies the gel poreswith steam.y The gel particles'sotreated may 4then be brought intocontact with the aqueous impregnating solution ofboron compound withoutencountering gel breakage. and impregnation thereof effected. Also, itis possible to prevent gel breakage ofthe dried, temperedchromia-alumina gel particles by evacuating the` same before contactingWith the impregnating solution. i-The advantage of the present catalystover those of the prior art is thata homogeneous active' catalyticsurface of chromia-alumina-boria is obtained and that .the activityinreforming petroleum hydrocarbons of the yresultant three-componentcomposite is distinctly improved as compared with chromia-aluminacomposite which had not Vbeen composited lwith boria. Thus, .thecatalyst de- 8 It would appear that the advantages derived in reformingwith the present catalyst are due to the specific promoting effect ofthe specified quantities of boria when the same are combined withchromia-alumina cogel of the above-recited composition range.

While certain details referred to `in the foregoing description havebeen directed to catalyst preparation in which chromia-alumina gel isemployed in the form of spheroidal particles, it is to be realized thatit is within the purview of this invention to use chromia-alumina gelsof any other desired form or shape.

The following non-limiting illustrative examples will serve morespecifically to point out 'the process of the invention and the improvedresults in activity obtained with the catalyst prepared in accordancewith said process.

Example 1 A chromia-alumina hydrogel was prepared from the followingreactants:

Solution A: 47.5 pounds sodium aluminate made up to a volume of 10gallons with distilled water;

Solution B: 48 pounds, chromic acetate, the acetate to chromium ratio ofwhich is adjusted within the approximate range of 2.6 to 2.8 and thenmade up to a volume of 13 gallons with distilled water, providing asolution containing 0.92 mole CrzOa per liter.v

Solutions A and B were pumped separately under pressure through heatingcoils to an ecient mixing nozzle. The solutions were heated to about 110F. and mixed in equal volumes at a total rate of 1200 cc. per minute.The resulting stream of hydrosol flowed over a divider into a column ofD.T.E. (diesel turbine engine) light oil. The hydrosol set to beads ofhydrogel and the resulting hydrogel beads were sluiced from the bottomof the forming tower with a 20 percent by weight aqueous solution ofammonium sulfate. The sluicing solution was maintained at a pH of 8.5 bythe addition of sulfuric acid. Since the pH of the hydrogel was about10.5, it was necessary to add sulfuric acid to the sluicing solution inorder to maintain the pH at 8.5. The bead hydrogel was aged for 24 hoursin the same solution that was used to sluice from the forming tower.After aging, the gel was Washed until v a sulfate-free wash Water wasindicated. The washed hydrogel had a product concentration of 21 percentby weight, and contained, on a dry basis, 33.5 percent by weight chromiaand 66.5 percent by weight alumina. The hydrogel was thereafterball-milled, dried at 260 `to 280 F. for 16 to 2() hours and thencalcined in air for 16 hours at 1000 F.

Example 2 The washed chromia-alumina hydrogel prepared as in Examplevlin -an amount of 3000 grams was ball-milled scribed herein, comprisingVan intimate composite of f :position which had not undergonecombination with boria.

with 48.4 grams of powdered boric acid. The resulting composite wasdried at 260 to 280 F. for 16 to 20 hours and then calcined in Iair for16 hours at 1000 F. The

resulting composite contained 63.4 percent by weight alumina, 31.9percent by weight chromia and 4.7 percent by weight boria. y

Example 3 The catalyst of Example 1 was used in reforming a blend of50/50 molar n-.heptane and cyclohexane. The catalyst was sized to 14-25mesh before charging tothe reactor. Fifty cubic centimeters (49.84grams) of the catalyst was placed in 'the catalyst zone of a reactor andactivated by allowing a stream of hydrogen to pass over it atatmospheric pressure for 16 hours while holding the catalyst bed at 1000F. In the reforming process before starting tto charge the reactants tothe catalystjzone, the temperature of thecatalyst was brought to about860,F. The blend of n-heptane and cyclohexane was passed downwardly overthe catalyst bed at a liquidl hourly space velocity of l. Hydrogen wasmixed with the hydrocarbon feedbefore it entered the reactor in theAratio of 6 mols of hydrogen to 1 mol of hydrocarbon charge. The total`mass spectrometer.

9 pressure within the system was held at 100 p.s.i.g. The reactants werepassed over the catalyst during a minute pre-run period, the productsbeing discarded. Then a 30 minute balance run was made. Temperature inthe catalyst -bed was measured by means of a movable coaxialIthermocouple. IDuring the balance run, the liquid was 10 catalyst and22.5 percent fresh catalyst were used to reform the /50 molarn-heptane/cyclohexane blend, according to the procedure of Example 3.The temperatures employed were 856, 917, 969, and 1021 F.

The results of reforming in accordance with the above Examples 3, 4, and5 are shown in Table I below:

TABLE I Reforming to mol Percent n-Heptane Converted Example CatalystTemp., l-C7 Toluene CH Con- MCP Benzene Cri-C2 Cri-C4 F. Yield, Yield,version, Yield, Yield Yield, Yield, n-C'z Chgd. CH Chgd. Feed Chgd.

Mol. Mol. Mol. Mol. Mol. Mal. Mol. Percent Percent Percent PercentPercent Percent Percent Chromia-Alumina Catalyst 1, 00S 5 14 95. 5 2 9613 of Example 1. Chromia Alumina Borla 981 14 13 98 1 96 17. 5 10Catalyst of Example 2. Catalyst of Example 2 988 12. 5 11. 5 94 12 8916. 5 11.5

(77.5% Regenerated from Ex. 4 and 22.5% fresh) Reforming at 950 F.

Example Catalyst n-C1 Coni-C1 Toluene CH MCP Benzene Cl-l-Cz Cyl-C4version, Yield, Yield Conv., Yield, Yield Yield, Yield, n-C Chgd. CHChgd. Feed Chgd.

Mol. Mol. Mol. Mol. Mol. Mol, Mol. Mol. Percent Percent Percent PercentPercent Percent Percent Percent 3 Chromia-Alumina Catalyst 18 2 72 66 2.5

of Example l. 4 Chromia Alumina Boria 40 13.5 6.5 92 2. 5 86.5 9. 6 5Catalyst of Example 2. l

5 Catalyst of Example 2 30 12 4 82 12 70 7. 5 5

(77.5% Regenerated from Ex. 4 and 22.5% fresh).

O1+Cq=sum of hydrocarbons containing 1 or 2 carbon atoms per molecule.Ca+04=sum of hydrocarbons contaiung 3 or 4 carbon atoms per molecule.

`tion. The overhead from this distillation and the two gas samples weregiven ya complete component analysis by A portion of the residue wasacid treated to remove olens. The untreated portion was submitted foranalysis, as Well as the acid treated portion. Ultimately, a completeanalysis of the run products was obtained. Four such runs were ma'de atlaverage catalyst temperatures of 8,55, 906, 959 and 1017 F. In eachease, a pre-run preceded the balance run. The reforming results obtainedare `set forth hereinafter.

Example 4 The catalyst from Example 4 was regenerated by burn- 'ing oiIcoke at 900 to 1000 F. Fifty centimeters (45.64 grams) of catalyst`having the composition of the catalyst oli-Example 2 and comprising77.5 percent regenerated In the above Table I (Examples 3 and 4), it isclearly shown that the boria-promoted catalyst is` more active for theconversion of n-heptane and cyclohexane than the unpromotedchromia-alurnina. The fresh boria-promoted catalyst converted 60 percentof the n-heptane at 27 F. lower temperaturetl'ian chromia-alumina.Furthermore, the addition of boria tochlromia-alumina nearly doubled`the yield of isoheptane. At 950 F. both n-heptane conversion andcyclohexane conversion were strongly enhanced by promotion with boria.The benzene yield increased from 66 to 86 percent. Example 5 illustratesthe effect of regeneration on the chrorniaealumina-boria catalyst.` Thetemperature required for conversion of 60 'percent of the normal heptanewas increased 7 F., while at 950 F. n-heptane and cyclohexane conversiondecreased about l0 percent. Nevertheless, the regenerated catalyst wasmore .active than the fresh unpromoted chromia-alumina catalyst.

Example 6 The catalyst of Example l was used to reform the naphthapetroleum fraction having lan octane number of 67 and a boiling range`of between about 180 and about 390 F. The charge was reformed to 98octane number (CFRR-l-S cc. TEL), at a liquid hourly space velocity of1, a hydrogen to hydrocarbon mole ratio of 6 and a pressure of p.=s.i.g.

Example 7` The results of reforming, in accordance with the aboveExamples 6 and 7 `are shown in Table II below:

ing in the gasoline range which comprises contacting the same underreforming conditions with a catalyst consist- TABLE II Gasoline, Vol.Percent Chg. Iso/normal Wt. Percent C4 Req., Chg. Example CatalystTemp., Vol. F. Percent l# C4l Cri-c Ce-l- Charge C4 C5 lry CokeChromia-Alumina (Catn- 993 83. 9 83. 4 75. 4 68. 5 0.5 0.51 0. 77 13. 40.10

lyst of Example 1). Chrorna-Alumina-Boria 972 84. 0 81. 9 75. 7 69. 1 2.1 0. 40 0. 57 13. 8 0. 63

(Catalyst of Example 2) The results of the above Table II clearlyillustrate the eifect of the addition of boria to chromia-alumina on thereforming catalyst activity. The boria-promoted catalyst was about 20 F.more active at 98 octane number than the unpromoted chromia-alumina.lThe improvement in activity of the present catalyst as compared with achromia-alumina catalyst is shown in Figure 2 of the attached drawing.This ligure shows the laver-age temperature required to producereformate of various octane ratings using chromia-alumina (33.5 percentCr2O3-66-5 percent' A1203) and a catalyst of the present inventioncontaining a small amount of boria in combination with the abovechromia-alumina (63.4 percent by weight Al2O3-'-31.9 percent by WeightCr2O3-4-7 percent by weight B203).

=In addition to reforming hydrocarbon mixtures falling in the gasolinerange, the catalyst of the present invention is useful in catalytioallypromoting various other hydrocarbon conversion reactions including, byway of example, the isomerization of parains and dehydrogenation ofnaphthenes. It is accordingly to be understood that the abovedescription is merely illustrative of the preferred embodiments of theinvention of which any variations may be made within the scope of thefollowing claims by those skilled in the art without departing from thespi-rit thereof.

We claim:

l. Aprocess for reforming a petroleum distillate boiling within theapproximate range of 60 F. to 450 F. which comprises ycontacting thesame at a temperature `between about 700 F. and about 1000 F. yat `aliquid hourly space velocity between about 0.1 and about in vthepresence of hydrogen under a pressure between about 100 and about 1000pounds per square inch gauge and a mola-r ratio of hydrogen tohydrocarbon between about liiand about with a catalyst consistingessentially of chromia, alumina and boria prepared by forming achromia-alumina hydrogel having a solids content consisting essentiallyof a major proportion of alumina and a minor proportion of chromia andcontaining between about 70 and about 90 percent by weight of waterresulting from mixing aqueous solutions of sodium ialuminate andychromic acetate to yield a hydrosol, controlling the 'sodiumto aluminumion ratio and the acetate to chromium ion ratio, in said solutions toeffect rapid gelation Vof said hydrosol to a hydrogel, aging thehydrogen so obtained in a mildly alkaline aging medium, washing the agedhydrogel, intimately combining the washed hydrogel with boric acid,drying andcalcining the resulting composite at a temperature not inexcess of 1000 F. to yield a chromia-alumina-boria catalystpconsistingessentially of l0 to 30 percent by weight of chromia, 50 to 89 percentby weight of alumina and l to 20 percent by weight of boria. r i 1 2. Aprocessfor reforming a hydrocarbon mixture boiling essentially ofchromia, alumina and boria prepared by forming a chromia-aluminahydrogel having a solids content consisting of a major proportion ofalumina and a minor proportion of chromia land containing between about70 and about 90 percent by weight of water resulting from mixing aqueoussolutions of sodium aluminate and chromic `acetate to yield a hydrosol,controlling the sodium to aluminum ion ratio and the acetate to chromiumion ratio in said solutions to elfect rapid gelation of drying andcalcining the resulting composite at a temperature not in excess of 1000F. to yield a chromia-aluminaboria catalyst consisting essentially of 10to 30 percent by weight of chromia, 50 to 89 percent by weight ofalumina, and 1 to 20 percent by weight of boria.

3. A method for preparing a catalytic composite of chromia, alumina andboria which comprises forming a chromia-alumina hydrogel having a solidscontent consisting of a major proportion of alumina and a minorproporjtion .of chromia and containing between about 7 0 Vand aboutpercent by weight of water resulting from mixing aqueous solutions ofsodium aluminate and chromic acetate to yield a hydrosol, controllingthe sodium to aluminumion ratio and the acetate to chromium ion ratio insaid solutions to effect rapid gelation of said hydrosol Vto a hydrogel,aging the hydrogel so obtained in a mildly alkaline aging medium,washing the aged hydrogel, intimately combiningV the washed hydrogelwith a boron compound thermally decomposable to boria, drying andcalciningtherresulting composite at `a temperature not in excess of 1000F. to yield a chromia-alumina-boria catalyst consisting essentially of10 to 30 percent byrweight of chromia, 50 to 89 percent by weight ofalumina, and 1 to 20 percent by weight of boria. f

4. A method for preparing. ar catalytic composite of chromia, `,aluminaand boria which comprises forminga chromia-alumina hydrogel having asolids content consisting essentially of a major. proportion of aluminaand a minor proportion of chromia containing between about 70 and 4about90 percent by weight of water resulting from mixing aqueous solutions ofsodium aluminate and chromic acetate to yield a hydrosol, controllingthe sodium to aluminum ion -ratio and the acetate to chromium ion ratioin said solutions to eifect rapid Lgelaton of said hydrosol to ahydrogel, aging the hydrogel so obtained in a mildly alkaline agingmedium, washing the aged hydrogel, ball milling said hydrogel with boricacid for a sufficient period of time to effect a resultant homogeneousproduct, drying and calcining the resulting composite at a temperaturenot in excess of 1000 F; to yield a chromia-alumina-boria catalystconsisting essentially of 24 to` 30 percent by weight of chromia, 60 to73 i percent by weight of alumina and 3 to 10 percent by weightReferences Cited in the le of this patent of boria.

5. A catalyst composition consisting essentially of 10 UNITED STATESPATENTS to 30 percent by Weight of Ch-rOma, 50 t0 89 Percent by2,098,959 Frey et 'al Nov. 16, 1937 weight of alumina and 1 to 2Opercent by weight of boria, 5 2,288,320 Morey June 30, 1942 resultingfrom the method of preparation set forth in 2,404,024 Baie et al July 161946 Claim 3- 2 523 686 E 1 s 6 6- A catalyst meting essentially of 24 w30 Percent 656304 Nhzgggezgfi; if; i322 by welght 0f chromla, 60 t0 73percent by Welght 0f 2,773,837 Gutzeit et al Dec. 11, 1956 alumina and 3to 10 percent by weight of boria, resulting 10 from ythe method ofpreparation set forth in claim 4. 2773845 Stover et al Dec' 11 1956

1. A PROCESS FOR REFORMING A PETROLEUM DISTILLATE BOILING WITHIN THEAPPROXIMATE RANGE OF 60*F. TO 450*F. WHICH COMPRISES CONTACTING THE SAMEAT A TEMPERATURE BETWEEN ABOUT 700*F. AND ABOUT 1000*F. AT A LIQUIDHOURLY SPACE VELOCITY BETWEEN ABOUT 0.1 AND ABOUT 10 IN THE PRESENCE OFHYDROGEN UNDER A PRESSURE BETWEEN ABOUT 100 AND ABOUT 1000 POUNDS PERSQUARE INCH GAUGE AND A MOLAR RATIO OF HYDROGEN TO HYDROCARBON BETWEENABOUT 1 AND ABOUT 20 WITH A CATALYST CONSISTING ESSENTIALLY OF CHROMIA,ALUMINA AND BORIA PREPARED BY FORMING A CHROMIA-ALUMINA HYDROGEL HAVINGA SOLIDS CONTENT CONSISTING ESSENTIALLY OF A MAJOR PROPORTION OF ALUMINAAND A MINOR PROPORTION OF CHROMIA AND CONTAINING BETWEEN ABOUT 70 ANDABOUT 90 PERCENT BY WEIGHT OF WATER RESULTING FROM MIXING AQUEOUSSOLUTIONS OF SODIUM ALUMINATE AND CHROMIC ACETATE TO YIELD A HYDROSOL,CONTROLLING THE SODIUM TO ALUMINUM ION RATIO AND THE ACETATE TO CHROMIUMION RATIO IN SAID SOLUTIONS TO EFFECT RAPID GELATION OF SAID HYDROSOL TOA HYDROGEL, AGING THE HYDROGEN SO OBTAINED IN A MILDLY ALKALINE AGINGMEDIUM, WASHING THE AGED HYDROGEL, INTIMATELY COMBINING THE WASHEDHYDROGEL WITH BORIC ACID, DRYING AND CALCINING THE RESULTING COMPOSITEAT A TEMPERATURE NOT IN EXCESS OF 1000*F. TO YIELD ACHROMIA-ALUMINA-BORIA CATALYST CONSISTING ESSENTIALLY OF 10 TO 30PERCENT BY WEIGHT OF CHROMIA, 50 TO 89 PERCENT BY WEIGHT OF ALUMINA AND1 TO 20 PERCENT BY WEIGHT OF BORIA.